/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.coders;



import java.util.List;



/**

 * An abstract base class to implement a {@link Coder} that defines equality, hashing, and printing

 * via the class name and recursively using {@link #getComponents}.

 *

 * <p>A {@link StructuredCoder} should be defined purely in terms of its component coders, and

 * contain no additional configuration.

 *

 * <p>To extend {@link StructuredCoder}, override the following methods as appropriate:

 *

 * <ul>

 *   <li>{@link #getComponents}: the default implementation returns {@link #getCoderArguments}.

 *   <li>{@link #getEncodedElementByteSize} and {@link #isRegisterByteSizeObserverCheap}: the

 *       default implementation encodes values to bytes and counts the bytes, which is considered

 *       expensive. The default element byte size observer uses the value returned by {@link

 *       #getEncodedElementByteSize}.

 * </ul>

 */

public abstract class StructuredCoder<T> extends Coder<T> {

  protected StructuredCoder() {}



  /**

   * Returns the list of {@link Coder Coders} that are components of this {@link Coder}.

   *

   * <p>The default components will be equal to the value returned by {@link #getCoderArguments()}.

   */

  public List<? extends Coder<?>> getComponents() {

    return getCoderArguments();

  }



  /**

   * {@inheritDoc}

   *

   * @return {@code true} if the two {@link StructuredCoder} instances have the same class and equal

   *     components.

   */

  @Override

  public boolean equals(Object o) {

    if (o == null || this.getClass() != o.getClass()) {

      return false;

    }

    StructuredCoder<?> that = (StructuredCoder<?>) o;

    return this.getComponents().equals(that.getComponents());

  }



  @Override

  public int hashCode() {

    return getClass().hashCode() * 31 + getComponents().hashCode();

  }



  @Override

  public String toString() {

    StringBuilder builder = new StringBuilder();

    String s = getClass().getName();

    builder.append(s.substring(s.lastIndexOf('.') + 1));



    List<? extends Coder<?>> componentCoders = getComponents();

    if (!componentCoders.isEmpty()) {

      builder.append('(');

      boolean first = true;

      for (Coder<?> componentCoder : componentCoders) {

        if (first) {

          first = false;

        } else {

          builder.append(',');

        }

        builder.append(componentCoder.toString());

      }

      builder.append(')');

    }

    return builder.toString();

  }

}